This application claims all benefits of Korean Patent Application No. 10-2007-0132416 filed on Dec. 17, 2007 in the Korean Intellectual Property Office, the disclosures of which are incorporated herein by reference.
This patent application is an improvement of Korean Patent Application No. 2005-98713, filed by the applicant of the present invention.
A joint actuator for generating an actual motion of robots is an electric-mechanical system composed of an electric motor, a gear, and a link mechanism. The joint actuator is associated with a lot of internal disturbances, such as backlash and ripple, and structural vibrations. Further, since a humanoid robot should be driven in such an environment that the robot coexists with human beings, an unexpected contact with a human being or a contact with the environment can be a source of external disturbance, at any time.
Such disturbances may be an obstacle when humanoid robot actuators follow desired COM (center of mass) and ZMP (zero momentum position) trajectories in the conventional whole body coordination control structure. In a severe case, a humanoid robot may lose stability and fall over.